docs: def fromSuccessResponse(cls, success_response, signed_only=True):
          """Create a C{L{SRegResponse}} object from a successful OpenID
          library response
          (C{L{openid.consumer.consumer.SuccessResponse}}) response
          message
  
          @param success_response: A SuccessResponse from consumer.complete()
          @type success_response: C{L{openid.consumer.consumer.SuccessResponse}}
  
          @param signed_only: Whether to process only data that was
              signed in the id_res message from the server.
          @type signed_only: bool
  
          @rtype: SRegResponse
          @returns: A simple registration response containing the data
              that was supplied with the C{id_res} response.
          """
          self = cls()
          self.ns_uri = self._getSRegNS(success_response.message)
          if signed_only:
              args = success_response.getSignedNS(self.ns_uri)
          else:
              args = success_response.message.getArgs(self.ns_uri)
  
          if not args:
              return None
  
          for field_name in data_fields:
              if field_name in args:
                  self.data[field_name] = args[field_name]
  
          return self